Recombinant asparaginyl-tRNA synthetase from the human filarial parasite, Brugia malayi

ABSTRACT

Recombinant asparaginyl tRNA synthetase from human filarial parasite Brugia malayi. The enzyme is used in an assay for inhibitors of the synthetase and can be used as an antigen for producing antibody inhibitors of the disease, either monoclonal or polyclonal. The antibodies can be used to detect the synthetase and related enzymes. In particular, the synthetase can be used to produce an antibody to be used for detecting filarial nematodes. The synthetase can be used to produce adenylated nucleosides.

GOVERNMENT RIGHTS

This work was performed under National Institutes of Health Grant(NIAID) 08-K1A101019-A-PSA. The U.S. Government has certain rights inthis invention.

This is a divisional of copending application(s) Ser. No. 08/441,534filed on May 15, 1995, now U.S. Pat. No. 5,561,054.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a major Brugia malayi enzyme which is abiologically active, recombinant asparaginyl-tRNA synthetase. Thissynthetase functions specifically to aminoacylate tRNA with the aminoacid asparagine. Isolation of the filarial enzyme facilitatesexploration of structure-function relationships relevant to cognate tRNAbinding and biological activity for new drug development againstfilarial diseases. Further, the synthetase is used in an assay forinhibition or promotion of activity of the enzyme by various compounds.The enzyme is used for producing antibodies used in assays to detectfilarial nematodes in biological tissues. The synthetase can also beused to detect antibodies to the synthetase in a biological tissue.

(2) Description of Related Art

Lymphatic filariasis is caused by infection with the filarial nematodesBrugia malayi, Brugia timori, Wuchereria bancrofti and Onchocercavolvulus which collectively infect about 200 million persons throughoutthe world. The filarial nematodes cause lymphatic filariasis(elephantiasis) or onchocerciasis (river blindness). New controlstrategies for these parasites seek to characterize important parasiteantigens and biochemical pathways to serve as targets for vaccine or newdrug development (Philipp, M., et al., Ann Rev. Microbiol. 42 685-716(1988)). There is also a need to develop assays for filarial nematodes.The aminoacyl-tRNA synthetases (AARS) are a group of enzymes whoseprimary function is to specifically attach amino acids to the3'-adenosine of their cognate tRNAs in a two step process which involvesthe formation of an enzyme bound aminoacyl-adenylate intermediate(Carter, T. W., Ann. Rev. Biochem. 62 715-748 (1993)). These enzymesthus play a crucial role in ensuring the fidelity of proteinbiosynthesis by discriminating against incorrect aminoacylation and thusare fundamental to the growth and replication of all forms of life. Thestructural basis for AARS specificity lies primarily in mechanismsresponsible for the recognition of cognate tRNAs. The 20 AARS of bothprokaryotes and eukaryotes can now be divided into two classes based onshort peptide sequence motifs and catalytic domain topologies: aRossmann fold for class I and an antiparallel β fold for class II(Eriani, G., et al., Nature 347 203-206 (1990); and Cusack, S., et al.,Nature 347 249-255 (1990)).

In the course of immunological studies of filarial parasite antigens,the gene encoding an immunodominant 63 kDa peptide in B. malayi was alsofound within the genome of another major human filarial parasite, O.volvulus the organism which causes onchocerciasis (Nilson, T. W., etal., Proc. Natl. Acad. Sci. USA 85 3604-3607 (1988); and Kron, M., etal., Mol. Biochem. Parasit. 52 289-292 (1992)). When originallydescribed, the derived amino acid sequence of the B. malayi gene productwas thought to have no similarity with previously known proteins.Subsequent to recognition of a second class of AARS in 1990 (Eriani, G.,et al., Nature 347 203-206 (1990); and Cusack, S., et al., Nature 347249-255 (1990)), reanalysis of the B. malayi antigen primary structurerevealed the presence of one, and possibly two, allowing for thepossibility of a frame-shift error in the determination of the genesequence, structural motifs characteristic of the class IIaminoacyl-tRNA synthetases which strongly suggested that the antigen wasan asparaginyl-tRNA synthetase (Cusack, S., et al., Nucleic AcidsResearch 19 3489-3497 1991)). Previously, only a truncated 55 kDaportion of the B. malayi peptide had been expressed for immunologicalstudies. There is a need for a pure form of the completeasparaginyl-tRNA synthetase for the reasons discussed above.

OBJECTS

It is therefore an object of the present invention to providerecombinant DNA encoding an asparaginyl-tRNA synthetase of Brugiamalayi. Further, it is an object of the present invention to provideplasmids and bacteria which contain recombinant DNA and express thissynthetase. Further still, it is an object of the present invention toprovide an assay method which uses the synthetase as a basis for testingcompounds for enhancement or inhibition of the activity of thesynthetase. Further still, it is an object of the present invention touse the synthetase to produce an antibody which can be used in an ELISAassay. These and other objects will become increasingly apparent byreference to the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A is a photograph showing an ethidium bromide stained 1% agarosegel of PCR (PCR is polymerase chain reaction) deoxyribonucleic acidproducts obtained by reverse transcriptase PCR using specific primers.FIG. 1B is a photograph showing a Coomassie Brilliant Blue stainedSDS-PAGE gel of purified recombinant asparaginyl-tRNA synthetase (lane2) indicating a relative molecular weight of about 63 kDa based upon thesize standards (lane 1).

FIG. 2 is a graph showing asparagine substrate incorporation intovarious tRNA's catalyzed by a fusion protein of the synthetase with amaltose binding protein. Open squares are Escherichia coli tRNA, soliddiamonds are yeast tRNA and solid squares are calf liver tRNA.

FIG. 3 is a chart showing the alignment of three class II aminoacyl-tRNAstructural motif sequences with respect to the B. malayi and O. volvulusantigens and two established asparaginyl-tRNA synthetase.

FIG. 4 is a chart showing the steps of experiments of the presentinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to an isolated and purified protein whichcomprises recombinant DNA derived asparaginyl-tRNA synthetase of Brugiamalayi.

Further, the present invention relates to a recombinant DNA encoding anasparaginyl-tRNA synthetase of Brugia malayi.

Further, the present invention relates to a recombinant DNA encoding amaltose binding protein and asparaginyl-tRNA synthetase fusion protein,wherein the synthetase is removable by cleaving with Factor Xa.

Further still the present invention relates to an Escherichia colicontaining recombinant DNA encoding an asparaginyl-tRNA synthetase ofBrugia malayi.

Further, the present invention relates to an assay method whichcomprises: providing an isolated and purified protein which comprises arecombinant DNA derived asparaginyl-tRNA synthetase of Brugia malayi inan aqueous solution with a compound to be tested for an affect onactivity of the synthetase; and determining the effect on activity ofthe synthetase by the compound.

The present invention also relates to a process for asparaginylaminoacylation of tRNA which comprises: contacting a mixture of proteincomprising a tRNA and asparagine with an isolated and purifiedrecombinant DNA derived aminoacyl-tRNA synthetase of Brugia Malayi so asto aminoacylate the tRNA with asparagine.

The present invention relates to an assay for detection of filariasis inan animal which comprises providing a biological sample from the animalsuspected of containing filarial nematodes; and detecting aminoacyl-tRNAsynthetase in the sample from the nematodes with an antibody to arecombinant DNA derived asparaginyl-tRNA synthetase of Brugia malayi. Inthis assay the synthetase is used to produce a polyclonal or monoclonalantibody in the conventional manner. The antibody can be labeled or usedin a sandwich type assay.

Finally the present invention relates to an assay for detection offilariasis in an animal which comprises providing a biological samplefrom the animal suspected of containing an antibody to filarialnematodes; and binding the antibody with a recombinant DNA derivedasparaginyl tRNA synthetase of Brugia malayi.

The recombinant DNA is carried in Escherichia coli ATCC 69768. Thisstrain was deposited under the Budapest Treaty on Mar. 23, 1995 and isavailable upon request by strain name and number.

ATCC 69768 includes plasmid pMALCR1 which encodes a maltose bindingprotein used for isolation of the fusion protein by affinitychromatography and is used extensively by the prior art. This type offusion protein is described in detail in Current Protocols Supplement10, 16.6.1 published by New England Biolabs, Beverly, Fla. Factor Xa isused to cleave the maltose binding protein from the protein of interest.

The DNA encoding the synthetase can be incorporated in a non-infectivevirus, such as a baculovirus and used as a vaccine. A preferredbaculovirus host cell SK21 available from Michigan State University,Plant Biology, East Lansing, Mich. 48824.

Confirmation of recombinant asparaginyl-tRNA synthetase activity by thepresent invention represents the first example of a eukaryoticasparaginyl-tRNA synthetase that has been cloned, expressed andpurified, and thus can provide the means by which structure-functionrelationships of another member of the class II AARS can be studied. Thetruncated protein described in the prior art was missing a 8 KDa peptidesequence containing the characteristic motif 3 of the class II enzyme inthe C-terminal region which is required for active site formation andaminoacylation activity.

The fact that the Brugia malayi synthetase was originally identified asstrongly immunogenic, is understandable in view of what is known aboutAARS antigenicity in other species. In the group of human autoimmunediseases known as the idiopathic inflammatory myopathies, antibodieshave been identified against several human class II aminoacyl-tRNAsynthetases; histidyl-, threonyl-, alanyl- and glycyl-tRNA synthetases(Targoff, I., et al., J. Clin. Invest. 91 2556-64 (1993); and Love, L.A., et al., Medicine 70 360-374 (1991)). Anti-AARS antibodieseffectively inhibit enzyme aminoacylation activity in vitro, and areable to immunoprecipitate their respective cognate tRNAs (Bunn, C. C.,et al., J. Exp. Med. 163 1281-1291 (1986)). Therefore, it has beenhypothesized that tRNA binding sites may be antigenic, representinganti-idiotype epitopes. Because segments of the homodimer interface ofthe synthetase may function in tRNA, ATP and amino acid binding,identification of important antigenic regions is difficult orunpredictable without the benefit of a biologically active synthetase ofthe present invention.

The synthetase can be used to locate inhibitors. Such inhibitors are forinstance synthetic amino acid adenylates (Biou, V., et al., Science 2631404-1410 (1994)); and Belrhali, H., et al., Science 263 1432-1436(1994)). The synthetase can also be used to develop antibodies to theenzyme for use in vitro or in vivo in animals, particularly loweranimals and in assays. The synthetase is also useful forasparaginylation of tRNA.

EXAMPLE 1

To explore potential biological activity of the presumed B. malayiaminoacyl-tRNA synthetase, a 1615 base pair cDNA encoding the entirefilarial antigen peptide was amplified by reverse transcriptase PCRusing polyA enriched RNA extracted from adult female B. malayiparasites, and this cDNA was subcloned for expression of thecorresponding full length peptide. Successful efforts resulted in largescale overproduction and purification of the intact 63 kDa synthetasepeptide with only 3 non-parasite residues at the amino terminus of therecombinant protein which are derived from the maltose binding fusionprotein utilized to express the gene in Escherichia coli.

FIG. 1A shows ethidium bromide stained 1% agarose gel demonstrating PCRproducts obtained by reverse transcriptase PCR using AARS specificoligonucleotide primers. PolyA enriched RNA was extracted from adultfemale B. malayi parasites using standard techniques and 50 nanogramswas utilized to synthesize cDNA using reverse transcriptase (TIMESAVERcDNA synthesis, Pharmacia, Inc., Piscataway, N.J.). The resulting cDNAwas used as template for amplification of B. malayi antigen gene usingtwo gene specific oligonucleotide primers: 5':ATGACTGTTTATATTTGTCCAGAAACTGGAGAT (SEQ ID NO. 1) and 3':TTGAATTCTTATGGGACACATCGACCAACAAAGCGAGG (SEQ ID NO. 2), and 30 cycles ofamplification using the following thermocycler parameters: hot start at92° C. for 60 seconds, denaturation; 95° C. for 30 seconds, annealing:55° C. for 30 seconds, primer extension: 72° C. for 90 seconds, terminalextension: 5 minutes at 72° C. FIG. 1B shows in lane 2 CoomassieBrilliant Blue stained SDS-PAGE gel showing purified recombinantasparaginyl-tRNA synthetase (63kDa). Lane 1 shows the size standard.

EXAMPLE 2

Full length cDNA was subcloned into the plasmid pMAL-cR1 (New EnglandBiolabs, Beverly, Mass.) for large scale overproduction of therecombinant as a fusion protein with the 42 kilodalton maltose bindingprotein. Growth media in a 20 liter fermenter was seeded with culturesof the E. coli Inv α strain harboring a plasmid containing the filarialantigen cDNA, and growth at 30° C. From this culture induced with IPTG(isopropyl-β-D-thiogalacto-pyranoside), 40 grams of bacterial paste wasobtained. Milligram quantities of >95% pure recombinant (63 kDa) wasobtained for aminoacylation activity studies, following a series ofchromatographic purification steps which included gel filtration,affinity chromatography (amylose resin), and preparative Factor Xacleavage of the maltose binding protein fusion product.

EXAMPLE 3

Although the homology analysis of the B. malayi antigen amino acidsequence suggested that it might be an asparaginyl-tRNA synthetase, thesequence of the related O. volvulus peptide resembled that of anaspartyl-tRNA synthetase (Kron, M., et al., Mol. Biochem. Parasit. 52289-292 (1992)). To investigate potential amino acid and tRNA specificactivities of the recombinant filarial enzyme, aminoacylation studieswere conducted using both ¹⁴ C! labelled aspartic acid and asparagine,and unfractionated tRNAs from E. coli, yeast and calf liver. With thethree tRNAs no amino acid incorporation above control values wasobserved with ¹⁴ C! aspattic acid. Significant aminoacylation washowever found with ¹⁴ C! asparagine, with low incorporation into E.coli, intermediate into yeast and high incorporation into calf livertRNA. Substantial activity is measurable even prior to cleavage ofmaltose binding protein sequences from the filarial enzyme suggestingthat, as in the case of the seryl-tRNA synthetase from E. coli,quaternary structure is not perturbed by the additional 42 kDa of themaltose binding protein at the amino terminus nor does this additionsignificantly hinder conformational changes which might be associatedwith substrate binding. FIG. 4 shows the steps in this analysis.

FIG. 2 shows asparagine incorporation into tRNAs catalyzed by thepurified 125 kilodalton B. malayi antigen fusion protein with maltosebinding protein at various dilutions; □E. coli tRNA, ♦ yeast tRNA, ▪calf liver tRNA. Protein sample (10 μl, ca. 3.8 mg/ml undiluted) wasadded to 40 μl Tris (0.064 M) HCl buffer pH 7.6 containing: 0.1 mM L- ¹⁴C!-asparagine (98 cpm/pmol), 0.5 mM spermidine, 5 mM disodium ATP, 500μg unfractionated E. coli or yeast tRNA or 250μg calf liver tRNA. Afterincubation for 15 min at 37° C., the reaction was quenched with 50 μl of5% (w/v) TCA (trichloroacetic acid), and the mixture was spotted onto aWhatman GF-A glass fibre filter. The filter was then washed 3 times with5% TCA, and subsequently with ethanol, ethanol:ether, ether, dried andcounted for radioactivity. Parallel measurements made with ¹⁴C!-aspartic acid showed no incorporation above control values.

FIG. 3 shows alignment of the class II aminoacyl-tRNA synthetasestructural motifs (Cusack, S., et al., Nucleic Acids Research 19 265-269(1991)) sequences of the filarial antigens of B. malayi and O. volvulus.(antBM and antOV) with those of the asparaginyl-tRNA synthetases from E.coli (Anselme, J., et al., Gene 84 481-485 (1989)) (NRSEC) andSaccharomyces cervesiae (Bolle, P-A., et al., Yeast 8 205-213 (1992)).The published DNA sequences for antBM (Nilson, T. W., et al., Proc.Natl. Acad. Sci. USA 85 3604-3607 (1988)) for motif 2 and antOV (Kron,M., et al., Mol. Biochem. Parasit. 52 289-292 (1992)) for motifs 1 and 2have been corrected for frame shift errors. Residues conserved for thefour proteins are in bold type.

The new DNA sequence data for the B. malayi asparaginyl-tRNA synthetase(Kron, M., et al., Mol. Biochem. Parasit. 52 289-292 (1992))demonstrated a discrepancy with the previously published sequence(Nilson, T. W., et al., Proc. Natl. Acad. Sci. USA 85 3604-3607 (1988)),which produced a frameshift that obscured a typical class IIaminoacyl-tRNA synthetase motif 2a sequence (RAEK . . . SRTRRH) at aminoacids 314-324 (Cusack, S., et al., Nucleic Acids Research 19 265-269(1991)). Alignment of known asparaginyl tRNA synthetases from E. coliand S. cervesiae with both the B. malayi and O. volvulus enzymes nowdemonstrate typical conservation of active site motifs and tertiarystructure as shown in FIG. 3.

Given the high level of expression of message encoding this enzyme in B.malayi (Nilson, T. W., et al., Proc. Natl. Acad. Sci. USA 85 3604-3607(1988)), it is possible to speculate on the demand for asparaginyl-tRNAsynthetase activity in the adult female parasite. Class II AARS in otherspecies also function in the production of adenylated nucleotides,alarmones. The asparaginyl-tRNA synthetase of the present invention canbe used for this purpose (EMBL Grenoble Annual Report (1994)).Adenylated nucleotides (e.g. Ap₄ A) may play a variety of biologicalroles as signal molecules, regulating both gene expression and enzymeactivity (Bochner, B. R., et al., Cell, 37 225-232 (1984); and Segal,E., et al., Exp. Cell. Res. 167 119-126 (1986)). Since considerablemetabolic effort of the adult female parasite is devoted to nutritionand production of viable embryos and larvae, it is conceivable that thehigh level of asparaginyl-tRNA synthetase expression reflects unusualmetabolic demands associated with larval maturation and thus is a targetfor inhibition.

Ten years ago, the observation that filarial protein synthesis washighly sensitive and specific for certain new experimentalantihelminthics, lead to the belief that aminoacyl-tRNA synthetaseswould indeed be excellent targets for the development of new targeteddrug design (Walter, R. D., Trop. Med. Parasitol. 37 95 (1986)). Studiesof the crystal structure of a seryl-tRNA synthetase from E. colicomplexed with cognate tRNA and two synthetic seryl adenylateintermediates (Biou, V., et al., Science 263 1404-1410 (1994)); andBelrhali, H., et al., Science 263 1432-1436 (1994)) confirm thatinhibition of AARS catalytic sites is possible. tRNA binding domains ofthe AARS distant from the catalytic site are probably the best targetsfor specific and low toxicity enzyme inhibition, since such domains arelikely to be structurally different in the parasite and its host due todifferences in the evolution of their tRNA substrates.

The amino acid sequence of the t-RNA synthetase of the present inventioncan be used to prepare a DNA probe for isolation of other synthetases.This can be done by making a DNA probe and using PCR to isolate the DNAencoding the other synthetases. The DNA probe can be used to screen alibrary directly and in the PCR reactions.

The foregoing description is only illustrative of the present inventionand the present invention is limited only by the hereinafter appendedclaims.

    __________________________________________________________________________    SEQUENCE LISTING                                                              (1) GENERAL INFORMATION:                                                      (iii) NUMBER OF SEQUENCES: 14                                                 (2) INFORMATION FOR SEQ ID NO:1:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 33 Base Pairs                                                     (B) TYPE: Nucleic Acid                                                        (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Synthetic DNA                                                (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Brugia malayi                                                   (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1:                                      ATGACTGTTTATATTTGTCCAGAAACTGGAGAT33                                           (2) INFORMATION FOR SEQ ID NO:2:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 38 Base Pairs                                                     (B) TYPE: Nucleic Acid                                                        (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Synthetic DNA                                                (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Brugia malayi                                                   (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:                                      TTGAATTCTTATGGGACACATCGACCAACAAAGCGAGG38                                      (2) INFORMATION FOR SEQ ID NO:3:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 18 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Brugia malayi                                                   (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3:                                      MetArgGluHisPheTyrAsnAlaGlyTyrValGluValAlaProProThrLeu                        51015                                                                         (2) INFORMATION FOR SEQ ID NO:4:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 18 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Onchocerca volvulus                                             (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4:                                      MetArgGluHisPheTyrAsnAlaGlyTyrValGluValAlaProProThrLeu                        51015                                                                         (2) INFORMATION FOR SEQ ID NO:5:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 18 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Escherichia coli                                                (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5:                                      PheMetLeuTyrPheGlnLysAsnHisPheThrLysValSerProProIleLeu                        51015                                                                         (2) INFORMATION FOR SEQ ID NO:6:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 18 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Saccharomyces cerevisiae                                        (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6:                                      LeuHisArgPhePheAsnGluGlnGlyPhePheTrpValSerThrProLeuIle                        51015                                                                         (2) INFORMATION FOR SEQ ID NO:7:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 36 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Brugia malayi                                                   (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7:                                      LeuGlyAspValPheHisLeuHisCysSerTyrArgAlaGluLysSerArgThr                        51015                                                                         ArgArgHisLeuAlaGluTyrAlaHisValGluAlaGluCysProPheIleThr                        20253035                                                                      (2) INFORMATION FOR SEQ ID NO:8:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 36 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Onchocerca volvulus                                             (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 8:                                      AspAlaGlnTyrHisIleTyrPheGluLeuPheArgAlaGluLysSerArgThr                        51015                                                                         ArgArgHisLeuAlaGluTyrAlaHisValGluAlaGluCysProPheIleThr                        20253035                                                                      (2) INFORMATION FOR SEQ ID NO:9:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 36 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Escherichia coli                                                (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9:                                      LeuSerArgCysTrpThrLeuSerProCysPheArgAlaGluLysSerAspThr                        51015                                                                         ProArgHisLeuSerGluPheTrpMetLeuGluValGluMetCysPheValAsn                        20253035                                                                      (2) INFORMATION FOR SEQ ID NO:10:                                             (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 36 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Saccharomyces cerevisiae                                        (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10:                                     LeuSerLysIleTyrThrPheGlyProThrPheArgAlaGluAsnSerAsnThr                        51015                                                                         SerArgHisLeuAlaGluPheTrpMetLeuGluProGluValAlaPheAlaAsn                        20253035                                                                      (2) INFORMATION FOR SEQ ID NO:11:                                             (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 34                                                                (B) TYPE: Amino Acids                                                         (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Brugia malayi                                                   (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11:                                     TyrGlyThrCysProHisGlyGlyTyrGlyLeuGlyLeuGluArgPheIleCys                        51015                                                                         TrpLeuTyrAsnThrAsnHisIleArgAspValCysLeuTyrProArg                              202530                                                                        (2) INFORMATION FOR SEQ ID NO:12:                                             (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 25 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Onchocerca volvulus                                             (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 12:                                     MetGluProValProHisGlyGlyTyrGlyLeuGlyLeuGluArgTyrLeuXaa                        51015                                                                         PheLeuThrAsnThrAsnHis                                                         2025                                                                          (2) INFORMATION FOR SEQ ID NO:13:                                             (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 34 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Escherichia coli                                                (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 13:                                     GluGlySerAlaProHisGlyGlyPheGlyLeuGlyPheGluArgPheIleSer                        51015                                                                         TyrLeuTyrGlyAsnHisAsnIleLysAspAlaIleProPheTyrArg                              202530                                                                        (2) INFORMATION FOR SEQ ID NO:14:                                             (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 34 Amino Acids                                                    (B) TYPE: Amino Acid                                                          (C) STRANDEDNESS: Single                                                      (D) TOPOLOGY: Linear                                                          (ii) MOLECULE TYPE:                                                           (A) DESCRIPTION: Motif of Synthetase                                          (iii) HYPOTHETICAL: No                                                        (iv) ANTI-SENSE: No                                                           (vi) ORIGINAL SOURCE:                                                         (A) ORGANISM: Saccharomyces cerevisiae                                        (vii) IMMEDIATE SOURCE:                                                       (A) LIBRARY:                                                                  (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14:                                     TyrGlyThrValProHisSerGlyPheGlyLeuGlyPheGluArgLeuIleAla                        51015                                                                         TyrValThrGlyValGlnAsnValArgAspValIleProPheProArg                              202530                                                                        __________________________________________________________________________

We claim:
 1. A compound screening assay method for an effect onsynthetase activity which comprises:(a) providing an isolated andpurified full length, enzymatically active protein which comprisesrecombinant DNA derived asparaginyl aminoacyl-tRNA synthetase of Brugiamalayi in an aqueous solution with a compound to be tested for an affecton synthetase activity; and (b) determining the effect of said compoundon synthetase activity.
 2. The method of claim 1, wherein the effect isinhibition of synthetase activity.
 3. The method of claim 1, whereinsaid synthetase is encoded by the DNA which has motifs 1, 2 and 3 withthe sequences as set forth in SEQ ID NOS: 3, 7 and
 11. 4. The method ofclaim 1, wherein the synthetase is fused with a maltose binding protein.5. A process for asparaginyl aminoacylation of tRNA which comprises:(a)contacting a mixture of protein containing tRNA and asparagine with anisolated and purified full length, enzymatically active recombinant DNAderived asparaginyl aminoacyl-tRNA synthetase of Brugia malayi; and (b)asparaginyl aminoacylating the tRNA.
 6. The process of claim 5, whereinsaid protein is encoded by the DNA which has motifs 1, 2 and 3 with thesequences as set forth in SEQ ID NOS: 3, 7 and
 11. 7. The process ofclaim 5, wherein the synthetase is fused with a maltose binding protein.